The present invention relates to a device for sealing a refueling opening and, more particularly, to a device of this kind that is capable of preventing any leakage of substance to be refueled and vapor of the substance, of reducing burden incurred during the insertion and removal of refueling nozzles of various types, and of exhibiting an improved level of wear resistance.
A refueling opening of a fuel tank installed in a vehicle is, in general, provided with a refueling opening sealing device for the purpose of preventing substance to be refueled from evaporating and thus dispersing into the air during a refueling operation. Such a device is shown in FIGS. 3 and 4.
The device for sealing the refueling opening is provided at an inlet portion 32 of a refueling pipe 31 connected to a fuel tank of the vehicle, not shown, to seal the gap between the refueling pipe inlet portion 32 and a refueling nozzle 33. The device comprises a casing 36 fixed to the refueling pipe inlet portion 32, and a seal supporting member 35 provided in the casing 36 for supporting an annular elastic sealing member 34 which comes into contact with an outer peripheral surface of the refueling nozzle 33 while the refueling nozzle 33 is inserted.
The annular elastic sealing member 34 is formed of such a material as NBR (nitril rubber) or fluoro-rubber which exhibits oil resistance to a substance to be refueled, and the member 34 has an inner diameter D1 which is smaller than the outer diameter d1 of the refueling nozzle 33.
The seal supporting member 35 comprises a main body portion 35a to which the annular elastic sealing member 34 is heat-bonded, three engagement portions 35b engaging with the annular elastic sealing member 34, and a leg portion 35c fixed to the casing 36.
The casing 36 has a cylindrical shape and is mounted within the refueling pipe inlet portion 32. The casing 36 is in contact with a part of the annular elastic sealing member 34, whereby a cavity is defined between the casing 36 and the seal supporting member 35.
The above-described refueling nozzle sealing device, however, encounters the following problems.
Namely, because the outer diameter d1 of the refueling nozzle 33 is not constant and varies, it is required that sealing should be effected within a wide range covering every possible variation. However, if the inner diameter D1 of the annular elastic member 34 is made small, a combination with a refueling nozzle 33 of a certain type may result in that a large radial gap must be sealed; if such is the case, a large load is necessary during the insertion and removal of the refueling nozzle 33.
If the annular elastic sealing member 34 contacts with substance to be refueled and vapor of the substance, to become swollen therewith, since the amount of its swelling is greatly dependent on temperature, there is a risk that the above-mentioned radial gap that has to be sealed may change and cause a further increase in the load necessary during the insertion and removal of the refueling nozzle 33.
For the purpose of reducing the load necessary during the insertion and removal of the refueling nozzle 33, it is possible to reduce the coefficient of friction by coating PTFE (polytetrafluoroethylene) on the surface of the annular elastic sealing member 34. However, since the refueling nozzle 33 being inserted or removed not only slides on the surface of the annular elastic sealing member 34 but also applies a large load on the same surface with its leading end, there is a risk that such a PTFE coating may become peeled.
Another refueling opening sealing device is shown in FIG. 5, in which a nozzle guide member 37 is provided between a seal supporting member 35 and a annular elastic sealing member 34, that are such as those of the refueling opening sealing device shown in FIGS. 3 and 4.
With the above-described device, however, it is not possible to reduce the load necessary during the insertion and removal of the refueling nozzle 33, nor to solve problems concerning the wear resistance. Thus, the device shown in FIG. 5 encounters problems similar to those encountered by the device shown in FIGS. 3 and 4.